| Message ID | f8ac33588bdce2bbe008dd027aca4d2cb9253d41.1385501822.git.ydroneaud@opteya.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c index 6c4fc6338b26..8652c13f6ea2 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -669,6 +669,9 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf, if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count) return -EINVAL; + if (ex_hdr.cmd_hdr_reserved) + return -EINVAL; + response = (char __user *)(unsigned long)ex_hdr.response; if (response) {
As noted by Daniel Vetter in its article "Botching up ioctls"[1] "Check *all* unused fields and flags and all the padding for whether it's 0, and reject the ioctl if that's not the case. Otherwise your nice plan for future extensions is going right down the gutters since someone *will* submit an ioctl struct with random stack garbage in the yet unused parts. Which then bakes in the ABI that those fields can never be used for anything else but garbage." It's important to ensure that reserved fields are set to known value, so that it will be possible to use them latter to extend the ABI. The same reasonning apply to comp_mask field present in newer uverbs command: per commit 22878dbc9173, unsupported values in comp_mask are rejected. [1] http://blog.ffwll.ch/2013/11/botching-up-ioctls.html Link: http://marc.info/?i=cover.1385501822.git.ydroneaud@opteya.com Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> --- drivers/infiniband/core/uverbs_main.c | 3 +++ 1 file changed, 3 insertions(+)